# Want to build a 12 DC to a 220 AC converter.

Discussion in 'General Electronics Chat' started by amsunaakage, Nov 12, 2008.

1. ### amsunaakage Thread Starter New Member

Nov 12, 2008
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All i need is to know the circuit and the components of a 12 DC to a 220 AC converter.
I googled out before i made my post but i didnt find the support i was hoping to , thats why i joined this community, a friend of mine told me how he get all the help he needed from here and how you guys helped him with ideas ^^ plus the IRC channel .

</Amsuna>

2. ### blocco a spirale AAC Fanatic!

Jun 18, 2008
1,461
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Have you searched for "inverter"?

The general consensus is that it isn't possible to build a better, cheaper inverter than those available ready-made.

3. ### amsunaakage Thread Starter New Member

Nov 12, 2008
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One important question: When i run a device, equipment,.....etc, on the inverter on my car battery, while my car is not running, this will wear off my battery in how much time ?

In other words,i'm just sitting in my car using a device takes 220V from my 12V battery, logically i would say it will only run for few secs , probably less than that , after that i will need a push to start my car.

4. ### Audioguru New Member

Dec 20, 2007
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You forgot to say how much power you need at 220VAC.
It might be 1W or it might be 1000W. A huge difference.
The car battery might explode if it drives a 1000W inverter that has a 1000W load.

A car battery for a medium size american car has about 80Ah of capacity. So it can supply 40A for 2 hours. The power from the battery is 40A x 12V= 480W. The inverter is not perfect so it converts some of the battery power to heat so the output of the inverter is about 384W.

An inverter can be simple and have a square-wave output. It can be more complicated and have a modified sine-wave output or it can be very complicated and have a pure sine-wave output. You forgot to say which one.

5. ### awright Well-Known Member

Jul 5, 2006
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Do you want to go through the exercise of building an inverter and understanding how it works (and how to repair it when it burns out), or do you just want to power some 220V device from your car? If the latter, inverters are a dime a dozen these days and it's just not practical to roll your own. If the former, plan on frying a few power transistors as you work out the bugs. I built a few decades ago before they were commonly on the market or when they were extremely expensive and spent a lot of time getting them to work satisfactorily (or sometimes not) with my desired loads.

It is important to analyze the power demand of whatever you want to drive, as described by Audioguru, to determine whether it is practical even with a perfect inverter. No amount of sophistication in design will get around the basic power consumption of your load translated down to the battery voltage. Then you have to factor in 70% or 80% efficiency of your inverter, depending on how sophisticated your design is. Then try to determine how sensitive your load is to power stability and waveform. Lots of loads do not like the harmonic content in square wave or "modified sine wave" (which actually should be called "modified square wave") inverters. Rolling your own true sine wave inverter could be quite a challenge.

awright

6. ### amsunaakage Thread Starter New Member

Nov 12, 2008
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Yes sure, and i would like this thread to move to the projects forum, it was a mistake to post this thread here in general, when my intention was to build it myself, and learn through the way.

The thing is that i have a lot of junk (Old transistors, ICs, capacitors, Res,....etc) i have dozens of each, i remove them from old boards and pack them up in small jars .

You wont believe how much stuff i have here, and ATM i am not capable of buying anything so i was hoping to get use of what i already have, and if there was something i need to buy i will get it next month.

I already got the circuit design from some googling , but i prefer the hard way, trial and error way (Like today i was soldering a wire to a battery when i over heated it and it exploded in my face, where m eyes where so close to it, thank God it was close).
I must get a new solder.
I'd like to know more about:
- Square-wave.
- Modified Sine-wave.
- Pure Sine-wave.

</Amsuna>